基于栖息地恢复对群落不同种群演化影响的模拟

通过建立基于栖息地恢复的多种群演化动力学模式,模拟了不同群落结构的不同物种种群的演化特点。模拟结果发现了两类灭绝机制,揭示了(1)小规模栖息地的恢复对群落中的弱小物种的影响是非常有限的,不会给弱小物种种群带来灭绝风险。大幅度的栖息地增加几乎使所有的物种种群都在最初数百年中内都有出现一定的增加,特别是竞争能力最强的物种,其幅度的增加最为显著,但次最强的物种种群可能会在千年左右灭绝。群落内幸存的种群将经历3个阶段迅速壮大(增加)阶段震荡阶段稳定阶段;(2)存在着协同现象,栖息地减少所导致种群的协同演化规律与栖息地恢复所导致的种群的演化规律两者之间既有共同点,又有不同点。毁坏是一种破坏,大规模的栖息地的恢复对已适应于破坏后新环境的某些物种也可能是一种威胁,这类似于生态入侵的初始阶段。

The simulation study of different population evolution in community based habitat restoration

It is well known that habitat fragmentation with human activities has made some species go extinction. Naturally, an inverse question appears: would man-made habitat restoration be beneficial to species persistence as natural conservation settlement? Based on this, a dynamical model was set up and the evolution characteristics of various populations in different communities were simulated in this paper. The results disclose two kinds of intrinsic species extinction mechanism. (1) The first kind of species extinction mechanism, i.e. poor species extinction in short lags time (ten-year scale). A large scale of habitat restoration instead of small quantities threatens species persistence and inevitably brings extinctions of some poor species, which provides some references for the considerations of natural conservation size. (2) The quasi-second mechanism of population extinction, i.e. species extinction phenomenon of some better ones. When the habitat restoration proportion is larger than the habitat occupancy rate of the strongest population, it is extremely complex for the orders by competition capability in equilibrium and not strictly abides by some special rules. Habitat enlargement causes nearly all species to extend their domains to a degree, especially the strongest one who colonizes remarkably more habitat. However, such cases would not last long and several better species would be in danger in about one thousand years after a period of adaptation to environment with the survivors except the best one experiencing three evolution stages of ascending, fluctuating and leveling. Obviously, habitat enlargement or restoration is rewarding to most species but catastrophic to several better individuals, which rings an alarm in species conservation. Additionally, cooperative development is opened out in this paper. Different from habitat destruction, habitat restoration brings some species to cooperate in pairs with the best and the poorest ones coming through increasing habitat occupancy continuously. Environmental protection is necessary and impeding. However, men should realize that excessive habitat restoration, equipollent to habitat destruction, is a kind of breach to an adaptive community. So, whether restoration or destruction, the degree should be primarily held.